1. Field of the Invention
The present invention relates to interferometric fiber optic gyroscopes (IFOGs). More particularly, the present invention relates to an IFOG having double the sensitivity, reduced angle random walk (ARW), and increased bias stability compared to an IFOG having the same fiber coil length and loop diameter. The present invention also relates to an IFOG that has the same gyro performance of a conventional IFOG, but that uses only half the fiber coil length of the conventional device.
2. Background of the Invention
As is well-known, in an interferrometric fiber optic gyroscope (IFOG), an optical fiber is wound in a circular or looped shape and acts as a sensing device to detect a Sagnac phase difference for two counter-propagating waves in presence of rotation. The product of the length and diameter (LD product) of the wound fiber sensing-coil determines, to a large degree, the sensitivity of the gyroscope. Generally speaking, the greater the LD product, the greater the sensitivity and stability of the device, and the lower the random noise. However, large coil volume resulting from greater fiber length or larger loop diameter (to achieve a higher LD product) requires increasingly bulky packages for the gyroscope device, especially when compared to other technologies such as the ring laser gyroscope (RLG) or hemisphere resonant gyroscope (HRG).